Devices for introducing gas into a metal melt



April 30, 1968 K. RTTIGER ET AL 3,380,727

DEVICES FOR INTRODUCING GAS INTO A METAL. MELT Filed Dec. 29, 1965 United States Patent Oftice 3,3%,727 Patented Apr. 30, 1968 3,380,727 DEVICES FR INTRDUCING GAS INT() A METAL MELT Kari Rttiger and Arniilt Diener, Dortmund, Germany,

assignors to Dortmund-Herder Huttenunion Aktiengesellschaft, Dortmund, Germany Filed Dec. 29, 1965, Ser. No. 517,219 Claims priority, application Germany, Jan. 9, 1965,

s claims. (ci. 26e-34) ABSTRACT OF THE DISCLOSURE In a degasication plant including a vessel to receive the melt to be degasiiied, the vessel having an entry pipe for immersion in a ladle containing the melt, a device for introducing gas into the metal melt through the entry pipe of the degasitication vessel, the device including a gas pipe for supply of gas, the pipe extending through the wall of the entry pipe and having a terminal end on the inner side of the latter and a cap, which is made of refractory porous material, detachably secured to the terminal end of the pipe, the cap projecting inwardly from the wall of the entry pipe and through which the gas is dispersed therein.

This invention relates to degasitication of metals and is concerned with a device for introducing gas into a metal melt. In the degasitication of metal melts in vacuo, the melt to be handled is transferred from a ladle into a degasitication vessel, which is arranged above it, the degasication vessel having in its bottom a pipe, whose lor/er end is immersed in the ladle. To assist the ow of the melt from the ladle upwardly through the pipe and into the degasification vessel a current of gas can be caused to tlow upwards in the pipe. In order to introduce the gas ilow, depending on circumstances, either a porous brick can be disposed in the ladle beneath the mouth of the pipe and be connected to a gas supply, or a gas pipe leading into the interior of the pipe is passed through the wall of the latter.

The second method mentioned is distinguished by greater constructional simplicity but has the disadvantage that the gas stream bubbles out close to the inner wall of the pipe, which gives rise to considerable erosion of the refractory lining of the pipe.

According to this invention the gas is introduced through a replaceable cap provided on the mouth of the gas inlet pipe, the cap, which is made of porous refractory material, projecting inwardly from the wall of the pipe leading upwardly into the degasication vessel. Experience has shown that with the aid of a cap of this type it is possible tor the gas current to be dispersed over the cross-section of the pipe and therefore diverted from the refractory lining of the pipe to an extent sucient to keep erosion within tolerable limits.

On the other hand the cap itself is subject to considerable erosion and other wear, but since it is detachable, this circumstance is not of great importance, because the cap can be readily replaced whereas the replacement of the entire connecting pipe is troublesome and time consuming and constitutes a considerable interruption to operation of the plant.

In the preferred embodiment of the invention, an intermediate threaded spigot piece to which the cap is screwed, is disposed between a supply pipe leading to the outside and to the cap. Irrespective of the size (diameter) of the supply pipe this intermediate spigot can be of such dimensions that it provides support for the cap, which would be dilicult to achieve if the cap were to be connected direct to the supply pipe.

It is preferable that the spigot piece should also be replaceable, which can best be achieved by connecting to the supply pipe a threaded sleeve, which serves as a fastening for the other end of the spigot piece. If, as may occur, the cap cannot then be detached from the spigot piece, by detaching the latter from the supply pipe the replacement can readily be effected.

One embodiment of the invention is illustrated in the accompanying drawing, in which,

FIGURE l is a longitudinal section through the entire arrangement, and

FIGURE 2 is a corresponding section on an enlarged scale of the ringed area designated at I in FIGURE 1.

Referring to the drawings, there is seen in FIGURE 1 the lower part of the wall 1 of a degasication vessel for steel melts, to the bottom opening 2, in which there is connected by means of flanges 3 a pipe 4 open at the bottom. The pipe 4 is made up of a cylindrical steel casing 5, a refractory lining 6 and a refractory jacket 7. During degasication the pipe is immersed in a ladle containing the melt, the ladle being situated beneath the vessel.

In order to convey the gases which are to be introduced into the pipe 4 for the above mentioned reasons, there is provided a gas supply pipe 8 terminating in a cap indicated generally at 9. The supply pipe 8 is led from above through the refractory jacket 7, bent inwardly at 11, and connected to the cap 9 by means of an intermediate spigot piece 10 in the manner shown in detail in FIGURE 2.

The cap 9, which is made of porous refractory material, is provided with an internal screw thread 12, by means of which it is detachably secured to the end 13 of the intermediate spigot piece 10, the latter having a central locating ange 10 which is accommodated in a recess in the cap 9. The lining 6 is cut away to provide a recess and seating for the cap and ange 10 of the spigot piece which latter projects obliquely inwards and downwards from the lining 6. The spigot piece 10 in turn is provided at the opposite end with a screw thread 14, by which it is detachably screwed into a counterbore in a sleeve 15, which is joined fast to the supply pipe 8.

The incoming gas from the supply pipe 8 flows through the sleeve 15 into an axial bore 16 in the intermediate spigot piece 16, said bore having its outlet at the outer end face of the latter. The gas, under pressure, can thus penetrate into the pores of the cap 9 and passes out of the outer surface of the latter.

What is claimed is:

1. In a degasitcation plant comprising a vessel to receive the melt to be degasied, said vessel having an entry pipe for immersion in a ladle containing the melt, a device for introducing gas into the metal melt through the entry pipe of the degasitication vessel, said device comprising a gas pipe for supply of gas, said pipe extending through the wall of the entry pipe and having a terminal end on the inner side of the latter and a cap, which is made of refractory porous material, detachably secured to the terminal end of the pipe, said cap projecting inwardly from the wall of said entry pipe and through which the gas is dispersed therein.

2. In a degasication plant comprising a vessel to receive the melt to be degasiiied, said vessel having an entry pipe for immersion in a ladle containing the melt, which pipe includes an outer insulation layer,a device for introducing gas into the metal melt through the entry pipe of the degasication vessel, said device comprising a gas pipe for supply of gas, said pipe extending lengthwise of the insulation layer and having a terminal end on the inside of the pipe and a cap, which is made of refractory porous material, detachably secured to the terminal end of the pipe, said cap projecting inwardly from the wall of said entry pipe and through which lthe gas is dispersed therein.

3. In a degasification plant comprising a vessel to receive the melt to be degasitied, said vessel having an entry pipe for immersion in a ladle containing the melt, a device for introducing gas into the metal melt through the entry pipe of the degasification vessel, said device comprising a gas pipe for supply of gas, said gas pipe extending through the wall of the entry pipe and having a terminal end inside the wall of the latter a cap, which is made of refractory porous material, detachably connected to the terminal end of the pipe, the connection between the gas pipe and the cap being by means of an intermediate spigot piece, the spigot piece having a screw thread to receive the cap, said cap projecting inwardly from the wall of the pipe.

4. A device according to claim 3, in which the spigot piece is detachably secured at one end t0 the gas supply plpe.

4. 5. A device according to claim 3, in which a threaded sleeve is connected to the supply pipe, the spigot piece being detachably secured to the sleeve.

References Cited UNITED STATES PATENTS 2,562,096 7/1951 Herrman 239-432 2,809,107 10/1957 Russell 266--34 2,966,294 8/1961 John 266-34 3,056,595 l0/l962 Knuppel et al. 266-34 3,071,362 l/l963 Lorenz 266-34 3,154,404 10/1964 Lorenz 75-49 X 3,320,053 5/1967 Lehman 75-49 X 3,330,645 7/1967 Demoustier et al. 266-34 J. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner. 

